You have heard parents speaking of their children and saying how fast they are growing. This growing is all thanks to the osteoblasts and osteoclasts. Before I go any further I think it best to clear up what these blasts and clasts are all about. On the cellular level, osteoclasts remove bone tissue and osteoblasts build bone tissue. In short, these two remodel bone. In children, mostly infants, one hundred percent of their skeleton is remodeled, so it is not so far to say they grow fast. Now bone is relatively light weight. This is because of the relationship between the osteoblasts and the osteoclasts. Without the removal of the bone tissue which is the job of the osteoclasts, the osteoblasts would keep making bone tissue, and in doing so make it very thick, and thus, making the bone heavier.
Now the work of the osteoblasts and osteoclasts do not stop during the years after maturity. As I am writing this, my osteoblasts and osteoclasts maybe hard at work. In adults they get to work every 3 months or so. Our bones are constantly changing. Maybe not the extent of younger humans, but the average adult has about ten percent of their bones remodeled every year. But even though these osteoblasts and osteoclasts seem like a well oiled machine, sometimes things go wrong (image below is what is supposed to happen).
That last paragraph makes osteoblasts and osteoclasts out to be something terrifying; almost like being eaten from the inside out. But these help us in more ways that keeping our bones healthy and strong. For example, when a bone is broken. A broken bone has a few steps to heal, from quickly forming a clot to stabilize the bone, to creating fiber of collagen (“the major protein in bone and connective tissue”). After all this is done, the last step and line of defense are the osteoblasts and osteoclasts. “Osteoclasts and osteoblasts spend months remodeling bone by replacing the bone callus with harder compact bone.” These elements are crucial for our survival. They may go mad in some cases, but, that said, it is thanks to this team of destroy and create that we are able to grow and rebuild.
Please feel free to comment on what you thought of the blog, or other physical anthropological subjects you would like me to cover. (animation below is an example of what the osteoblasts and osteoclasts do).